import "server-only";
import { AppError, authenticateWorker, forbidden, getEnv } from "@autoscholar/core";
import type { computeWorkers } from "@autoscholar/db";
import { db } from "./db";
import { clientIp, ipInCidrs, viaPublicProxy } from "./ip";

/**
 * Internal worker API guard: rejects anything that came through the public tunnel (Caddy adds X-Forwarded-*),
 * optionally enforces the private CIDR allow-list, checks the protocol version, then the worker bearer token.
 */
export async function requireWorker(req: Request): Promise<typeof computeWorkers.$inferSelect> {
  const env = getEnv();
  if (viaPublicProxy(req)) throw forbidden("internal API is not reachable through the public gateway");
  const ip = clientIp(req);
  if (ip && !ipInCidrs(ip, env.INTERNAL_API_ALLOWED_CIDRS)) throw forbidden("source network not allowed");
  const pv = req.headers.get("x-protocol-version");
  if (pv && pv !== "1") throw new AppError("protocol_mismatch", `unsupported worker protocol ${pv}`, 426);
  const auth = req.headers.get("authorization");
  const bearer = auth?.startsWith("Bearer ") ? auth.slice(7) : null;
  return authenticateWorker(db(), bearer);
}

export function assertInternalNetwork(req: Request): void {
  if (viaPublicProxy(req)) throw forbidden("internal API is not reachable through the public gateway");
}